Equatorial Stratospheric Waves Induced by Diabatic Heat Sources

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  • 1 Dept. of Meteorology, University of Hawaii, Honolulu 96822
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Abstract

The problem of finding the equatorial stratospheric response to prescribed tropospheric heat sources is treated by using a linearized primitive system on a Mercator map projection. The perturbation geopotential is assumed to be symmetric about the equator. Eastward propagating heat sources are prescribed at 20° latitude with zonal wavenumbers 1 and 2 and a period of about 16 days. They excite a substantial response near the equator with maximum zonal wind perturbation in the vicinity of 18 km, which perhaps corresponds to the lower regime of the observed Wallace-Kousky waves. However, no significant response occurs above 20 km in the equatorial stratosphere, although the zonal wind perturbation exhibits a weak maximum (<1 m sec−1) near 26 km. Presumably, diabatic heat sources at different latitudes (rather than 20°) are responsible for exciting the upper regime of the Wallace-Kousky waves.

Abstract

The problem of finding the equatorial stratospheric response to prescribed tropospheric heat sources is treated by using a linearized primitive system on a Mercator map projection. The perturbation geopotential is assumed to be symmetric about the equator. Eastward propagating heat sources are prescribed at 20° latitude with zonal wavenumbers 1 and 2 and a period of about 16 days. They excite a substantial response near the equator with maximum zonal wind perturbation in the vicinity of 18 km, which perhaps corresponds to the lower regime of the observed Wallace-Kousky waves. However, no significant response occurs above 20 km in the equatorial stratosphere, although the zonal wind perturbation exhibits a weak maximum (<1 m sec−1) near 26 km. Presumably, diabatic heat sources at different latitudes (rather than 20°) are responsible for exciting the upper regime of the Wallace-Kousky waves.

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